<!DOCTYPE html>
<html lang="en">
<head>
    <script>
      var aaa = {};

      var abc = {gid:"123",id:"234"};


      console.log(abc);
      if (aaa.abc === undefined)
      {
        console.log("没有此值");
      }
      else
      {
        console.log("有有有");
      }


    </script>
    <meta charset="UTF-8">
    <title>测试</title>
</head>
<body>

</body>
</html>